Evaluation of intraocular proton beam irradiation complications after choroidal melanoma treatment

Purpose
The aim of the research was to evaluate of intraocular complications after proton beam therapy of choroidal melanomas.

Material and methods
A total 105 patients (48 female and 57 male) from Department of Ophthalmology and Ocular Oncology of University Hospital in Cracow, who received proton beam radiation due to choroidal melanoma were enrolled. The mean age was 52.3 years (51.8 y. in females, 52.6 y. in males). Total irradiation dose was 60 cGy and it was applied in 4 fractions per 15 cGy (on 4 consecutive days). We evaluated the incidence of complications classifying patients by age, tumor location, tumor thickness, longitudinal and transversal basal diameter and follow-up period, which ranged between 5 and 57 months.

Results
Complications of intraocular irradiation were observed in 33 out of 105 treated patients. Retinopathy occurred in 18 cases, including 4 patients with macular edema. Neuropathy was confirmed in 8 patients, secondary glaucoma in 6 cases; we noted 9 cases of initial or progress existing cataract, 4 cases of dry eye syndrome and 1 patient with central retinal vein occlusion. A statistically significant positive correlation was demonstrated between the length of the follow-up period and the incidence of complications, which were more common and more severe with the longer follow-up period. There was no statistically significant correlation between the incidence of complications and patient’s age, tumor location, tumor thickness as well as longitudinal and transversal basal diameter.

Conclusions
All forms of radiation therapy used in intraocular tumors are associated with some risk of complications; proton beam radiotherapy is not free of that risk, either.